The present invention relates to a signal processing system and more particularly to a wave shaping technique for permitting the rapid evaluation of signal echo amplitude data on a pulse by pulse basis.
Generally, in signal processing systems such as radar or sonar systems, wherein echo signals are utilized to provide target information, various techniques have been proposed to improve the ability of the system to resolve multiple targets with less interference from system characteristics or noise. With the advent of track-while-scan computers, target location and estimation techniques have become particularly important in providing a basis for identifying targets under different environmental conditions. Most prior target detectors and location estimators relay upon the shape of the antenna scan profile and the number of hits per scan (with the particular antenna pattern), as the antenna passes through the area of the target, to provide accurate target detection. The accuracy of such detectors and estimators, however, is dependent upon the reproducibility of the target echo pattern for a given antenna pattern. While conventional radar displays have been constructed to provide target echo patterns that provide strong signals and minimal interference in accordance with the above scanning, various problems have been encountered which limit the system performance. In particular, certain disturbances which occur with relatively great frequency have a significant effect on the target echo pattern so that weaker echoes are modified significantly from those of strong signal echoes. In addition, disturbances such as multipath transmissions, which are more unpredictable and occur with less frequency, also provide significant echo distortion which alters target echo patterns. As a result, the standard radar display devices have been ineffective in providing signal data output which will provide for increased target detection or improved signal content of target echo patterns for use by detection and estimation devices.
In view of the present trend toward computerized command control systems, there is therefore a real need for more effective techniques for providing patterns which will facilitate evaluation by target detection and location processors. Such techniques are required to allow the automatic tracking of targets for coordination with vehicle control systems for quick response to multiple threats. These automatic target detectors, however, must be able to obtain precise target amplitude versus azimuth data in order to increase the effectiveness of data analysis. The data should be obtained from the particular vehicle signaling system and must be able to account for multipath effects on apparent amplitude pattern of the target. In dealing with this problem, previous techniques have utilized cathode ray tube displays (A-scopes) and high speed rapidly advancing photographic film with limited success. Still other techniques have utilized sample and hold devices which require the manual positioning of a ranging gate to enclose a signal target or, alternatively, expensive memory systems to acquire data on many targets. All such techniques have suffered from high expense, difficulty in use, and lengthy post acquisition data processing which has curtailed their effectiveness. Consequently, application to real time threats in multiple target environments has been severely limited.
Accordingly, the present invention has been developed to overcome the shortcomings of the above-known and similar techniques and to provide a wave shaping technique for obtaining target amplitude versus azimuth information for use with target detection and location estimation processors.